I mean the aim of the game is to get the most sexual content to FAP right??
No. You made two false assumptions.
First, you assumed other people's behavior was like your own.
Secondly, you assumed the goal of the book or game was simply to fap.
If people just wanted to fap there are a million porn sites, adult image sites for those just wanting to fap.
Games and VN's offer something they don't. A story and the ability to interact and make choices.
For stories and such to have any real value there has to a be a level of immersion and the ability for the reader to connect.
That's why I wrote posts on this site about demographics and other stuff. Lots and lots of people don't simply fap to anything.
Most people don't even look at porn. The more shit beyond the normal the more off putting it is for the majority of people.
To be blunt you, me and everyone on this site compared to the over all population are the weirdos the anomalies. We are in the 35% of people or so that look at porn. We are also part of the smaller group that plays adult games and looks at visual novels and the like. Then our deviations from there put us into even smaller groups.
So flat out adding more dicks turns most people off. That can be if she is fucking multiple men at different times or at the same time. One way or another she is seen with a negative view and most guys are turned off by it. For that matter I'm turned off by it even with all the stuff I'm into.
Most guys want to act as if their GF was a virgin before them. They have no interest in knowing they dated another guy and don't want any details about it. Adultery & money are the two leading things when it comes to divorce. Most people are not ok with their partners having sex with someone else. To have a character in the book or story they are playing through have to deal with that kills immersion for them instantly. Thus makes the story worthless to them.